The invention relates to a separator plate for an electrochemical system. For example, the electrochemical system can be a fuel cell system, an electrochemical compressor, a humidifier for a fuel cell system, or an electrolyser.
Known electrochemical systems usually comprise multiple separator plates, which are arranged in a stack, so that every two adjacent separator plates enclose an electrochemical cell or a humidifier cell. The separator plates usually each comprise two individual plates, which are connected to one another along their rear sides facing away from the electrochemical cells or dehumidifier cells. For example, the separator plates can be used in order to electrically contact the electrodes of the individual electrochemical cells (for example fuel cells) and/or to electrically connect adjacent cells (series connection of the cells). The separator plates can also be used to dissipate heat produced in the cells between the separator plates. Waste heat of this kind can be produced for example at the time of conversion of electrical or chemical energy in a fuel cell. In the case of fuel cells, bipolar plates are often used as separator plates.
The separator plates or the individual plates of the separator plates each usually have at least one passage opening. The passage openings of the stacked separator plates, which openings are aligned or at least partially overlap with one another in the separator plate stack of the electrochemical system, then form media channels for feeding or discharging media. In order to seal the passage openings or the media channels formed by the passage openings of the separator plates, known separator plates also have bead arrangements, arranged one around each of the passage openings of the separator plate.
The individual plates of the separator plate can additionally have channel structures for feeding a medium or a plurality of media to an active region of the separator plate and/or for transporting media away. The active region for example can enclose or delimit an electrochemical cell or a humidifier cell. For example, the media can be constituted by fuels (for example hydrogen or methanol), reaction gases (for example air or oxygen) or can be present as a coolant in the form of fed media and can be constituted by reaction products and heated coolant as discharged media. In the case of fuel cells, the reaction media, i.e. fuel and reaction gases, are usually guided over the surfaces of the individual plates facing away from one another, whereas the coolant is guided between the individual plates.
The flanks of the bead arrangement arranged around the passage opening of the separator plate can have one or more openings. These openings are used to produce a fluidic connection between the passage opening of the separator plate and the active region of the separator plate or between the passage opening of the separator plate and a cavity formed between the individual plates of the separator plate. The cavity is used for example to guide a coolant between the individual plates of the separator plate.
It is known from document DE10248531A1 that the separator plate or at least one of the individual plates can additionally have one or more guide channels, which on an exterior of the bead arrangement are connected to the openings in the bead flank and are fluidically connected to a bead interior via the openings in the bead flank. A medium can pass through the bead arrangement much more specifically with the aid of guide channels of this kind. The efficiency of the electrochemical system can thus be increased.
However, the openings in the bead flanks necessarily bring about a reduction of the mechanical stability and elasticity of the bead arrangement. This reduction is all the greater, the lower the bead arrangement is arranged. At the same time, however, the shortest height possible of the bead arrangement is advantageous, in order to minimise the size of the separator plate stack and in order to accommodate more cells without increasing the height of the separator plate stack.